Internal combustion engines are known. The most common types of piston engines are two-stroke engines and four-stroke engines. These types of engines consist a relatively large number of parts, and require a numerous number of auxiliary systems, e.g., oiling, cooling and the like, for proper functioning.
GB2183726(A) discloses a double-action two-stroke internal combustion engine. The engine is provided with an exhaust valve that moves on and with respect to the piston rod and does not form an integral portion thereof. The exhaust valve is rearwardly tensioned by a spring and opens by a tenon when the piston moves to the other side. The exhaust takes place when the piston reaches the other side, and the exhaust valve closes as soon as the piston starts moving to the other side.
The disadvantages of '726 are; the need to produce the exhaust valve slidingly matching to the piston rod, the necessity to provide a spring and a mechanical opening mechanism to the valve, and, the inefficient gas exchange process.
U.S. Pat. No. 5,676,097(A) discloses a high-efficiency internal combustion engine provided with a double-acting piston cooperating with auxiliary feed inlet units. The exhaust opening is located at the center of the cylinder, and the inlet openings are located at the edges of the cylinder and use a valve (19).
US2012280513(A1) discloses a free piston engine. The engine is very long. A piston, located at each side of the engine is connected by means of an internal rod to the other piston. The engine contains liquid therein and the exhaust is carried out by means of a mechanical valve located at each side of the engine. The mechanical power is not received outside the engine but within the engine.
The '513 application suffers from the disadvantage that it requires a dedicated exhaust valve and a mechanism for operation thereof.
U.S. Pat. No. 4,831,972(A) discloses an internal combustion engine having the spark plugs located at a center thereof. The mechanical power received by the engine remains within the engine.
U.S. Pat. No. 6,722,322(B2) discloses an internal combustion engine comprising two pistons that form a kind of an engine head. An external spring serves to hold an internal plunger.
DE102008004879(A1) discloses a free piston engine, for example, for an excavator, that has a heat engine with free pistons, linear generator driven by the heat engine for generating electrical energy, and pump assembly driven by the heat engine for generating hydraulic and/or pneumatic energy.
U.S. Pat. No. 6,199,519(B1) discloses a free piston engine which is self-ignited without the need of spark plugs. No power is going out from the engine and the inlet and exhaust are provided at both sides of the cylinder side.
U.S. Pat. No. 4,385,597(A) discloses a two-stroke internal combustion engine having three pistons; one central piston and two side pistons moving with respect to the central piston.
U.S. Pat. No. 4,414,927(A) discloses a two-stroke oscillating piston engine having three pistons. Neither of the piston rods serve as an exhaust valve.
JP563192916(A) discloses a linear engine having three pistons.
GB2353562(A) discloses an internal combustion engine with a rigid piston/connecting rod unit and two combustion chambers, also with thermal insulation and water spray into the combustion chambers. A disadvantage of the engine of '562 is that it requires inlet and exhaust valves at each side of the engine.
It is the object of the present invention to provide a free piston engine that significantly reduces or overcomes the aforementioned disadvantages.
It is a major object of the present invention to provide a new method of gas exchange in an internal combustion engine.
It is a further major object of the present invention to provide a free piston engine that enables constant flow of pre-charged fresh air into and through the cylinder and through the piston rod regardless the position of the piston, and, through the exhaust system, irrespective of the combustion action taken at a given time.
It is a further object of the present invention to provide a new cycle process in an internal combustion engine which differs from an Auto cycle, Atkinson cycle, or two stroke cycle.
It is still another object of the present invention to provide a multifunctional piston.
It is yet another object of the present invention to provide a piston that functions as an inlet valve, and, a piston rod that functions as an exhaust tube and as an exhaust valve.
It is still a further object of the present invention to provide a free piston engine embodying direct low-pressure fuel injection.
It is yet another object of the present invention to provide a free piston engine embodying a traverse stressless action piston.
It is a further object of the present invention to provide a free piston engine which prevents compressed gas leakage by diverting the flow of gases to a longer path and reducing the convergence of gases toward the gap between the engine head and the piston rod.
It is still a further object of the present invention to provide a free piston engine having a piston rotation prevention mechanism.
It is still yet another object of the present invention to provide a free piston engine having a split sealing ring rotation prevention system.
It is also another object of the present invention to provide a free piston engine having electric generators at its perimeter.
It is still another object of the present invention to provide a free piston engine that transforms linear movement to rotational movement.
It is yet another object of the present invention to provide a low cost free piston engine.
It is a further object of the present invention to provide a new internal combustion engine that is efficient, have a small number of parts, have a high power to weight ratio, and significantly reduces air pollution and fuel consumption.